Microbial contamination of food, in hospitals, in animals, as well as in commercial and residential buildings continues to be a problem. In particular, pathogenic microbial contamination of fruits and vegetables has been on the rise, including contamination of fruits and vegetables in the field, during harvesting, transport and/or processing, by pathogenic microbes from animals, humans, organic fertilizer and/or water supply. Bacteria are estimated to cause some 24 million cases of diarrheal disease annually in the U.S. Over 40,000 cases of contamination by Salmonella were reported from 1983 to 1987 in laboratory surveillance data.
Several compositions and methods are available for reducing microbial contamination (e.g., Bailey et al., U.S. Pat. No. T964,007 and U.S. Pat. No. 4,074,058; Faergemann et al., WO/89/12469; Andrews et al., U.S. Pat. No. 5,490,992; Estrada, U.S. Pat. No. 5,599,571; Andrews, U.S. Pat. No. 5,569,461; Bautista et al., U.S. Pat. No. 6,045,846; Conners et al., U.S. Pat. No. 6,086,833; Bender et al., U.S. Pat. No. 6,287,617; Koefod et al., U.S. Pat. No. 7,090,882 Howarth et al., U.S. Pat. No. 7,182,966; Shane et al., U.S. Patent Application US 2002/0134317; and Hilgren et al., U.S. Patent Application US 2007/0098751), including those that contain oxidizers. However, prior art compositions that contain oxidizers continue to show low antimicrobial activity in the presence of organic contaminants, and especially at the lower temperatures used for processing, storing and transporting agricultural products. Also, the prior art's compositions have the additional problems of increased foaming and of the oxidizer gassing out of the solution due to bio-load and/or too low or too high pH, thus adversely impacting active ingredients and worker safety. Furthermore, higher levels of oxidizers are required to reduce bio-load and turbidity of the solutions used for antimicrobial treatment, which raises safety concerns when ingesting products that are treated with those compositions. In addition, the presence of plant material in the prior art solutions reduces the longevity of the oxidizer, thus reducing its antimicrobial activity and increasing the cost of production because of the need to replenish the oxidizer often.
Thus, there remains a need for improved compositions and methods for reducing microbial contamination.